The present disclosure relates generally to fault responsive control systems for a power grid. Fault detection and isolation is crucial to maintaining a healthy power grid. Extended exposure to fault currents can damage power grid components. The addition of distributed energy resources (DERs) to the power grid necessitates new means of fault detection and isolation. Whereas existing power grids with a radial distribution structure would only have fault current flowing in one direction, a power grid with DERs may have fault currents flowing in multiple directions from different power sources. Existing power grid control systems suffer from a number of shortcomings and disadvantages. There remain unmet needs including increasing fault responsiveness, increasing system reliability, and decreasing grid downtime. For instance, the presence of fault currents from multiple power sources may cause current control systems to misinterpret the magnitude and direction of fault current and therefore the location or existence of a fault. Furthermore, inaccurate fault detection and isolation reduces the service life of DERs. There is a significant need for the unique apparatuses, methods, systems and techniques disclosed herein.